import java.util.Stack;

public class MinStack {

    private Stack<Integer> stack;

    private Stack<Integer> minStack;


    public MinStack() {
        this.stack = new Stack<>();
        this.minStack = new Stack<>();
    }

    public void push(int val) {
        if (minStack.empty()){
            minStack.push(val);
        }
        if (val<=minStack.peek()){
            minStack.push(val);
        }

        stack.push(val);
    }

    public void pop() {
        if (!stack.empty()){
            if (stack.peek() == minStack.peek()){
                stack.pop();
                minStack.pop();
            }else {
                stack.pop();
            }
        }



    }

    public int top() {
        if (stack.empty()){
            return -1;
        }
        return stack.peek();
    }

    public int getMin() {
        if (minStack.empty()){
            return -1;
        }
        return minStack.peek();
    }



}
